WASHINGTON, July 21 -- The Federal Communications Commission approved a plan today requiring broadcasters to adopt technology allowing blind people to follow the action on television by listening to a narrator describe what is happening.

The rules are part of a broad plan to make telecommunications and new technology like wireless phones more accessible to people with disabilities. Of the 54 million people with disabilities in the United States, 8 million to 12 million have severely impaired vision.

"This is important to allow everyone to participate in the television experience," said William E. Kennard, the F.C.C. chairman. "Television is the modern equivalent of the public square."

The technology allows the user to turn on a secondary audio programming channel, where a narrator describes the action of a scene during pauses in the dialogue. Audiences can hear that an actor sadly buries his face in his hands, for example.

The commission will model its video description rules on guidelines governing closed-captioning technology for the hearing impaired.

The rules, which were adopted by a 3-to-2 vote, will require that network-affiliated broadcasters in the top 25 television markets use the secondary channel for roughly four hours per week, either as prime-time or children's programming, beginning in the spring of 2002.

Cable systems and satellite operators with 50,000 or more subscribers will have to provide the service for their most popular networks.

The dissenting commissioners questioned whether the agency had the statutory authority to impose the rules on the broadcast industry.

Live news shows, sporting events -- which often include play-by-play descriptions -- and talk shows would be exempt from the rules, because the action is generally covered in natural dialogue.

But the rules will cover local emergency information that is part of a newscast, or that interrupts regularly scheduled programming. And when emergency information scrolls across the screen, an aural tone will be required to alert people that important information has been provided. The emergency policy will take effect in a few months.

The video descriptions delivered over the secondary audio programming channel would be heard only when that channel is activated. All televisions made in the United States since the early 1990's have the
channel.

In some markets, however, the secondary channel is used for Spanish and other foreign language audio, a potential conflict. The cost of providing video descriptions is another concern among broadcasters.

The plan is limited to analog broadcasters, but could be applied to emerging digital broadcasters later. The commission intends to gather information and experience with this technology, officials said, to help
evaluate the possibility of expanding and improving the program.

Telephone calls to the National Association of Broadcasters were not returned today. A spokesman for the National Cable Television Association said that the group looked forward to reading the F.C.C. order, but that the industry should be able to create its own standards. Public television has been active in the video description effort for more than a decade.

WGBH in Boston, for example, began to narrate the popular programs "Masterpiece Theater" and "Nature" in the 1980's.

Margaret Pfanstiehl, the chairwoman of the National Television Video Access Coalition, called the proposal "a huge step forward."